<!DOCTYPE html>
<html lang="en" class="reftest-wait"
      reftest-displayport-x="0"
      reftest-displayport-y="0"
      reftest-displayport-w="800"
      reftest-displayport-h="1000">
<meta charset="utf-8">
<title>Scrolling shouldn't invalidate the fixed items</title>

<style>

.content {
  box-sizing: border-box;
  width: 200px;
  height: 200px;
  border: 1px solid black;
}

.fixed {
  position: fixed;
  top: 20px;
  left: 20px;
}

.reftest-no-paint {
  border-color: lime;
}

.distanceFromTop {
  margin-top: 240px;
}

.clip {
  width: 200px;
  height: 200px;
  overflow: hidden;
}

.transform {
  position: relative;
  will-change: transform;
}

body {
  margin: 0;
  padding: 20px;
  height: 3000px;
}


</style>

<div class="fixed reftest-no-paint content">
  <!--
    This fixed layer gets its own PaintedLayer above the page.
  -->
</div>

<div class="distanceFromTop clip">
  <!--
    This clip determines the potential pixels that can be affected by the
    animated transform, *in relation to the scrolled page*. If the page
    is scrolled, the clip moves relative to the fixed items, so the fixed
    items need to anticipate the transform getting between them.
  -->

  <div class="transform content">
    <!--
      This is an animated transform item. It can move freely but will be
      clipped by the .clip element.
    -->
  </div>

</div>

<div class="fixed reftest-no-paint content">
  <!--
    This fixed layer is above the animated transform, in z-order. The
    transform is clipped in such a way that initially, the clip doesn't
    intersect the fixed items, but once the page is scrolled, it does.
    So this fixed item must not share a layer with the lower fixed item.
  -->
</div>

<script>

function doTest() {
  document.documentElement.scrollTop = 100;
  document.documentElement.removeAttribute("class");
}
document.documentElement.scrollTop = 0;
document.addEventListener("MozReftestInvalidate", doTest, false);
// setTimeout(doTest, 500);

</script>
